Lightroom: discard standard previews for selected photos

It'd be great if Lightroom allowed discarding of standard previews for selected photos (like it does for 1:1 previews). My lightroom catalog and previews now fill my entire SSD. As of now I have to go and delete the entire folder and just have it rebuild previews for selected portions of my catalog. Ideally after discarding the standard preview it would keep a thumbnail sized copy for offline identification of the photo.